Fluid proof connector with insulated contacts



Aug. 18, 1970 A. L. NELSQN 3,525,053

FLUID PROOF CONNECTOR WITH INSULATED CONTACTS I Filed July 1,1968

2 Sheets-Sheet 1 I v M r l0 l7 l3 12-30 29 22 23 ll 24 IO l2 I7 23 I3 35 H 2| 39 l9v I5 28 40 FIG. 4

INVENTOE: ARTHUR LEE NELSON I Wag/3 A770 NEYS Aug. 18, 1970 A. L. NELSON 3,525,058

FLUI I D PROOF'CONNECTOR WITH INSULATED CONTACTS Filed. July 1, 1968 2 Sheet-Sheet 6 4| v 49 45 43 5e 57 so 52 *i 42 FIG.8

INVEN7'0E ARTHUR LEE NELSON United States Patent 3,525,068 FLUID PROOF CONNECTOR WITH INSULATED CONTACTS Arthur Lee Nelson, La .lolla, Calif., assignor to Electro Oceanics, Inc., a corporation of California Filed July 1, 1968, Ser. No. 741,508

Int. Cl. H01r 23/52 U.S. Cl. 339-41 '8 Claims ABSTRACT OF THE DISCLOSURE An electrical connector for underwater use is designed in such a manner that connections and disconnections can be effected while the connector is electrically energized. A plug body is provided with a forwardly projecting plug means having an exposed contact surface substantially flush with the plug means. A socket body in turn is provided with a socket having an interior socket contact with an exposed surface portion flush with the inner wall of the socket. A tumbler member of electrically insulating material is rotatably disposed in the socket. This member includes a channel receiving the plug means. The arrangement is such that rotation of the tumbler member and plug means received in the channel therein relative to the socket moves the tumbler member from an initial position in which the socket contact is recovered and insulated to a second position placing the plug contact into electrical engagement with the socket contact. The socket contacts can thus be continuously energized since they are never exposed to the surrounding water and the rotational motion assures a wiping action of the insulating interior surfaces of the socket against the plug contact surface prior to electrical engagement with the socket contact to assure a dry and fluid-tight contact.

This invention relates generally to fluid proof connectors and more particularly to an improved electrical connector for use under water wherein connections and disconnections can be effected under power.

BACKGROUND OF THE INVENTION In my US. Pat. No. 3,277,424, there are described in considerable detail electrical connectors primarily designed for eifecting connections under water, although the connectors themselves are useful in other fluid environments such as gases, or even in explosive atmospheres. The basic design feature in the foregoing types of connectors resides in the provision of a socket body having an elongated socket open at both ends for cooperation with a plug body having an elongated plug of dimensions corresponding to those of the socket and receivable in one end of the socket. The socket and plug, respectively, include socket and plug contacts intermediate their ends such that when the elongated plug is urged into one end of the socket, water or other fluid in the socket is urged out the opposite end, and the interior surfaces of the socket and exterior surfaces of the plug are wiped clean of any fluid or other foreign matter. Thus, the integrity of the electrical connection when the plug contact is positioned within the socket contact is assured.

While plug and socket asemblies of the above described type will provide a waterproof connection once the connection has been made, the socket and plug contacts are necessarily exposed to the water prior to actually inserting the plug in the socket. Therefore, it is essential that neither of the plug nor socket contacts be energized until such time as the connection has been completed.

In my later US. Pat. No. 3,375,480, there is described a dummy or blind plug for use with the heretofore described connectors wherein the dummy plug can be in- 3,525,068 Patented Aug. 18, 1970 serted in the socket to cover and insulate the socket contacts from water. Under these conditions, the socket contacts may be energized and a connection to a plug contact effected by inserting the plug in one end of the socket in such a manner as to simultaneously slide out the dummy contact so that at all times, the socket contacts are insulated from the water. It is thus possible to eflect electrical connections under power. On the other hand, it is necessary that there be available a blind plug and since the blind plug itself is a separate element, it can become misplaced. There is also the possibility that the socket contacts might be energized inadvertently when the blind plug is not in position. Such an occurrence would result in an electrolysis action with the water taking place which would not only substantially short circuit the power source but would result in pitting and chemical deterioration of the socket contacts themselves.

BRIEF DESCRIPTION OF THE PRESENT INVENTION With the foregoing considerations in mind, the present invention contemplates an improved underwater connector in which connections and disconnections can be effected under water even with one set of contacts continuously being energized and wherein there is no possibility of the energized contacts ever being exposed to the surrounding water even if the plug should be inadvertently removed from the socket portion of the connector.

More particularly, this desirable end is realized by providing a plug and socket body similar in certain respects to those described in my heretofore first mentioned United States patent. In addition, however, there is provided a tumbler member of electrically insulating material retained in the socket body in a position to completely cover and insulate the socket contacts. This tumbler member includes a channel means for receiving the plug only when the tumbler member is in a given initial position. After receiving the plug, the plug and tumbler member itself are rotated in the socket to bring the plug contact into electrical engagement with the socket contact. During this rotation, a wiping action of the insulating surfaces which are flush with the respective contacts occurs to realize the variaus advantages of providing a clean and dry electrical connection.

The plug and socket bodies incorporate interlocking means so designed that it is not possible to separate the plug from the socket without again rotating the tumbler member back to its initial position wherein the socket contacts are completely covered and insulated. In this initial position, the plug can then be removed.

it will be evident that with an arrangement of the foregoing type, the various advantages of enabling electrical connections to be made under water under power conditions are realizable. Further, the live contacts or energized contacts are never at any time exposed to the water whether the plug is inserted or removed from the socket.

BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the invention will be had by now referring to the accompanying drawings, in which:

FIG. 1 is an exploded perspective view showing a plug body, socket body and tumbler member constituting the basic components of a first embodiment of the electrical connector of this invention;

FIG. 2 is a front elevational view of the plug body of FIG. 1;

FIG. 3 is a front elevational view of the socket body of FIG. 1 with the tumbler member assembled therein;

FIG. 4 is a side elevational view partly broken away of the assembled components in connected condition;

FIG. 5 is an exploded perspective view of a plug body, a socket body, and a tumbler member constituting the basic components of a second embodiment of the connector of this invention;

FIG. 6 is a cross section of the socket body taken in the direction of the arrows 66 of FIG. 5

FIG. 7 is a front elevational view of the socket body with the tumbler member assembled therein; and,

FIG. 8 is a side elevational view partly broken away of the various components of FIG. 5 in connected condition.

DETAILED DESCRIPTION OF THE INVENTION Referring to the first embodiment of FIG. 1, there is shown a plug body 10, a socket body 11, and a tumbler member 12. These components are molded and constitute waterproof electrically insulating material such as neoprene. As shown, the plug body 10 includes forwardly projecting plug means in the form of prongs 13, 14, 15, and 16. While four prongs are shown, it should be understood that additional prongs could be provided depending upon the number of multiple connections desired. On the other hand, it is only necessary that there be provided a single forwardly projecting prong in the event that only a single connection is to be effected.

In the embodiment of FIG. 1, electrical plug contacts are provided on each of the prongs. These plug contacts are imbedded in the rubber-like material of the prongs but each has an exposed contact surface facing laterally outwardly and in flush relationship with the surrounding ma terial of the prong. In the particular embodiment shown, the contacts are indicated in positions intermediate the ends of the prongs as at 17, 18, 19, and and side portions of the contacts as well as outwardly facing top surface portions are also exposed. Insofar as the structure is concerned, it is only necessary, that there be provided an exposed contact surface facing outwardly in flush engagement with the material of the respective plugs. The plug body 10 also includes a central bore opening 21 the purpose for which will become clearer as the description proceeds.

Referring now to the plug body 11, this structure includes a socket means in the form of a hollow interior defined in part by a smoothly surfaced cylindrical interior wall 22. Socket contacts as indicated at 23, 24, 25, and 26 are imbedded in the wall material of the socket body and have exposed contact surfaces flush with the interior cylindrical wall portions of the socket. These surfaces thus face generally radially inwardly. The socket body also includes a central forwardly projecting shaft 27 designed for reception in the central bore 21 of the plug body 10 when the elements are assembled. The purpose for this shaft structure will also become clearer as the description proceeds. The socket body structure is completed by a water escape outlet 28 which extends from the interior rear portion of the socket through the socket body 11 to the exterior.

Referring now to the tumbler member 12 shown in the exploded view of FIG. 1, this member constitutes a cylindrically shaped body having smoothly surfaced peripheral cylindrical portions 29 designed to engage the interior cylindrical wall 22 of the socket body 11. Channel means in the form of a plurality of cutout passages in the periphery such as indicated at 30, 31, 32 and 33 are provided as shown. These channels extend from the front of the member to the rear in directions generally parallel to and radially spaced from the central axis of the tumbler member 12. The tumbler member is also provided with a central bore or passage 34 for receiving the shaft 27 when assembled Within the socket body 11. Also, there is provided a reduced diameter cylindrical portion at the rear end face of the tumbler member as indicated at 35. The shaft 27 is provided with an annular groove 36 arranged to cooperate with a suitable C type Washer (not shown in FIG. 1) for holding the tumbler member in the socket all as will become clearer as the description proceeds.

In the front elevational view of the plug body 10 shown in FIG. 2, it will be noted that the outwardly facing exterior surfaces of the various plugs and associated flush contact surfaces are of convex cylindrical configuration. This cylindrical configuration corresponds precisely to the interior cylindrical wall 22 and also to the exterior cylindrical peripheral portion of the tumbler member 12. In FIG. 2, it will be noted that the central bore 21 includes a radially projecting longitudinally extending slot or passage 37 which swings downwardly interior of the plug 10 as indicated by the dotted lines to define a bayonet type slot.

In the front elevational view of the assembled tumbler member and socket body as shown in FIG. 3, it will be noted that the position of the tumbler member 12 in the socket is such that the socket contacts 23, 24, 25, and 26 are completely covered and insulated by the peripheral cylindrical surface portions of the member 12. The shaft 27 is provided with a laterally extending tab 38 towards its outer end. With the tumbler member 12 in the position shown in FIG. 3 in the socket body, it will be evident that the various channels are in positions to receive the plugs of the plug body and that the shaft 27 and tab 38 are positioned to be received through the bore 34 in the tumbler member 12 and in the bore 21 and passage 37 in the plug body 10.

Referring now to FIG. 4, there is illustrated the various plug prongs inserted in the channels of the tumbler member with the tumbler member in the socket body. It will be noted that a C type washer 39 is positioned in the annular groove 36 in the portion of shaft 27 passing from the front of the tumbler member. This arrangement keys the tumbler member within the socket body and prevents axial movement outwardly of the tumbler member from the body. On the other hand, the tumbler member is free to rotate about its central axis in the socket body. The space between the rear of the tumbler member and the rear wall of the socket body defines a plenum chamber 40 which is in communication with the water escape outlet 28 as shown.

In the connected position shown in FIG. 4, the socket body 11 has been rotated relative to the tumbler member 12 and plug body 10 approximately in a counterclockwise direction when viewed from the right end of FIG. 4 to place the plug contacts 17 and 19 in electrical engagement with the socket contacts 23 and 25 respectively. It will, of course, be understood that the other plug contacts will engage the other corresponding socket contacts when the parts have been relatively rotated as described. Further, it will be evident that the tab 38 on the end of the shaft 27 has been received in the bayonet slot structure defined by the end portion of the passage 37 so that the plug and socket bodies are locked together.

Referring now to the second embodiment of the invention shown in FIG. 5, there is provided a plug body 41, a socket body 42, and a tumbler member 43 all of insulating waterproof material such as neoprene. In the embodiment of FIG. 5, the plug body 41 includes forwardly extending plug means 44 including plug portions 45 and 46 within which there are imbedded plug contacts 47 and 48 having exposed surfaces flush with the forward ends of the portions 45 and 46. This plug means also includes to the rear of the portions 45 and 46 a cylindrical portion 49 of slightly greater diameter than the central portion 44 of the plug means.

The socket body 42, in turn includes a front wall 50 having a central socket opening 51 and laterally spaced cutout portions 52 and 53. The interior of the socket body 42 is hollow as indicated at 54 and the rear portion of this interior communicates with a water escape outlet passage 55.

The tumbler member 43 of the second embodiment show in FIG. 5 again comprises a cylindrically shaped body having a smooth peripheral cylindrical surface 56 and a fiat smoothly surfaced rear face 57 and front face 58. A central bore 59 passes through the member and includes lateral channels 60 and 61 extending in parallel spaced relationship to the central axis of the member from the front wall 58 to the rear wall 57.

The diameter of the central bore 59 in the member corresponds to the external diameter of the plug means 44 and the channels 60 and 61 are dimensioned to snugly receive the plug portions 45 and 46 of the plug member. The cylindrical portion 49 of the plug member in turn is dimensioned to be received in the cylindrical portion 51 of the front wall 50 in the socket body 42.

With particular reference to the cross section of the socket body shown in FIG. 6, it will be noted that suitable socket contacts are provided at 62 and 63, these contacts being imbedded in the rear flat wall of the interior of the socket in radially and circumferentially spaced positions so that surface portions are flush with this flat wall as shown. In FIG. 6, it will be noted that the water escape passage 55 extends entirely across the rear flat wall of the socket body.

In the front elevational view of FIG. 7, the tumbler member 43 is shown disposed entirely within the socket body in such a manner that the front wall 50 overlaps the front face 58 of the tumbler member so that the tumbler member is confined within the interior 54 of the socket. The relative diameters of the front wall entrance bore 51 and that of the bore 59 in the tumbler member will be clear from FIG. 7. In the initial position of the tumbler member 43 shown in FIG. 7, it will be evident that the rear face 57 of the tumbler member covers and insulates completely the socket contacts 62 and 63 in view of the circumferential positioning of these contacts.

FIG. 8 illustrates the components of FIG. in assembled relationship wherein the plug means 44 has been received in the socket body 42. In this position, it will be evident that the rear face 57 of the tumbler member 43 is in flush engagement with the flat rear interior wall of the socket. Also, the cylindrical portion 49 of the plug means is journaled within the opening 51 in the front wall 50 of the socket described in FIG. 5. The relative positions of the plug and socket bodies are the same as illustrated in FIG. 5; that is, no relative rotation has been effected. However, it will be evident that when the components are plugged together as shown in FIG. 8 a subsequent relative rotation between the plug and socket bodies of approximately 45 will result in the plug contacts 47 and 48 being placed into electrical engagement with the socket contacts 62 and 63 described in FIGS. 6 and 7.

OPERATION OF THE FIRST EMBODIMENT OF THE INVENTION Referring back to FIGS. 1 through 4 illustrating the first embodiment of this invention, its operation will now be described.

Initially, the socket body is provided during its manufacture with the tumbler member 12 within the socket and keyed thereto as by the C-type washer 39 received within the annular groove 36 shown in FIG. 4. Since the cylindrical peripheral portion such as 29 of the tumbler member 12 corresponds in diameter to the interior cylindrical wall 22 of the socket body, the tumbler member fits in fairly close snug engagement within the socket and requires a certain amount of friction to effect sliding action between its peripheral surface and the inside surface of the wall. In its initial position of insertion in the socket, the tumber member 12 is oriented as illustrated in FIG. 3 so that the socket contacts, as described, are completely covered and insulated by the peripheral cylindrical surface portions such as 29 of the tumber member. It will be clear accordingly that even when the plug body is disconnected from the socket body 11 and all of the components are under water, the socket contacts are completely insulated from the water and may carry a given voltage at all times.

In effecting an electrical connection, the various plug prongs are inserted in the channels of the tumbler member 12. In this insertion, the plug body 10 must be rotationally oriented such that the tab 38 on the shaft 27 of the socket body is properly received within the passage 37 forming part of the bore 21 in the plug body. There is thus avoided any ambiguity as to which plugs are to be received in which channels. With the plugs aligned with the proper channel, the plug body 10 is urged towards the socket body 11 to completely slide the plugs in the channels until the front face of the tumbler member engages the flat front face of the plug body 10. The tab 38 on the shaft 27 is then aligned with the bayonet slot structure of the passage 37 so that the plug body and socket body may be rotated relatively to each other. This rotation would be in a counterclockwise direction for the socket body 11 when viewed from the right in FIG. 4. The prongs of the plug being received in the tumbler member channels will necessarily cause a rotation of the tumbler member along with the plug body relative to the socket body 11 and after approximately 45 of rotation, it will be evident that the plug contacts will then be placed into electrical engagement with the socket contacts.

Because of the snug configuration of the peripheral cylindrical portion of the tumbler member with the interior cylindrical wall portion of the socket body, a wiping action will occur during this rotation so that the previously exposed plug contacts will be wiped and dry of any water or moisture prior to electrical engagement with the socket contacts. It will also be understood, of course, that as the plug contacts are urged into the tumbler member channels, water in the socket will be purged through the plenum chamber and water escape outlet passage 28 as indicated by the arrow in FIG. 4. Moreover, there will result a certain amount of wiping action during the longitudinal insertion of the plugs in the tumbler member channels.

An advantage of the particular structure described in FIGS. 1 to 4 is the fact that the dual wiping action of the plug contacts is effected during any connection. Thus, as noted, the plug contacts are wiped during longitudinal insertion and then further wiped by the interior cylindrical wall of the socket body during the rotational movement.

The extent of rotational movement is determined by the arcuate extent of the bayonet slot portion of the passage 37. Thus, when the proper rotation has been effected, the tab 38 will abut against the end of this arcuate passage portion. This tab, of course, will serve to lock the plug body to the socket body and prevent the same from being inadvertently pulled apart.

To disconnect the plug and socket, it is first necessary to effect a relative rotation between the bodies in opposite directions to those initially provided to effect the connection. This rotation will thus bring the tab back into alignment with the main longitudinal portion of the passage 37 and then permit Withdrawal of the various plugs from the tumbler member channels. The rotation of the tumbler member as a consequence of this latter rotation will again cause the peripheral cylindrical surface portions of the tumbler member to completely cover and insulate the socket contacts prior to any possibility of the plugs being removed. Therefore, the socket contacts are at all times completely insulated from the surrounding water whether the plug is in position or not. These contacts may thus be continuously energized without any danger of shock or of exposure to water which might otherwise result in electrolysis and chemical pitting of the contacts.

OPERATION OF THE SECOND EMBODIMENT OF THE INVENTION Referring now to FIGS. 5 to 8, the complete operation of the second embodiment of this invention will be described.

As in the case of the first embodiment, the socket body 42 is initially provided with the tumbler member 43 incorporated within the hollow interior 54. From FIG. 8, it will be evident that the overlapping portion of the front wall 50 with respect to the front surface 58 of the tumbler member 43 assures that the tumbler member will be retained within the socket body. As in the case of the tumbler member for the first embodiment, the peripheral cylindrical surface corresponds to the interior cylindrical wall of the socket body so that a snug fit of the tumbler within the socket body exists and some friction against rotation of the tumbler exists so that the tumbler will normally remain in its initial position within the body.

This initial position is illustrated in FIG. 7 wherein it will be evident that the socket contacts 62 and 63 are completely covered and insulated from any surrounding water. These contacts may thus be continuously energized or carry a given voltage without fear of any short circuiting or any shocks.

If it is now desired to effect an electrical connection, the plug means 44 is inserted into the front bore 51 in the front wall 50 of the socket and the plug portions 45 and 46 are received in the channels 60 and 61 of the tumbler member. During this longitudinal insertion, a purging of any water in the channels 60 and 61 of the tumbler member occurs, this water being urged from the rear in terior of the socket through the water escape passage 55. When the plug means 44 is completely received within the tumber member, the cylindrical portion 49 is received within the bore 51 of the front wall 50 of the socket and is thus journaled therein. In this position, as will be noted from FIG. 8, the plug portions 45 and 46 extend beyond the overlapping portion of the front wall 50 of the socket so that the plug and tumbler member may be rotated as a unit. In this particular position, the exposed plug contact surfaces 47 and 48 are substantially flush with the rear surface 57 of the tumbler member and are also in wiping engagement with the rear fiat wall of the socket body carrying the contacts 62 and 63.

In the relative positions illustrated in FIG. 8, no rotation between the plug and socket has as yet taken place. However, when the components are in the position illustrated, they may be relatively rotated to thus circumferentially position the plug contacts 47 and 48 into electrical engagement with the socket contacts 62 and 63. This rotation results in a wiping of the exposed plug contacts by the rear flat wall portion of the socket so that when electrical engagement between the plug and socket contacts is effected, the plug contacts will be wipped free and clear of any water or moisture. Further, it will be evident that upon such rotation of approximately 45, the plug portions 45 and 46 will be locked in the socket as a consequence of the overlapping front wall 50 of the socket. The plug and socket bodies cannot thus be separated and in order to effect a separation, it is necessary to re-rotate the plug and tumbler member to their initial positions. In this position, as described, the socket contacts are again completely covered and insulated by the rear fiat surface of the tumbler member so that at all times they are insulated. The plug may then be withdrawn from the socket.

While not illustrated in the embodiment of FIGS. through, 8, suitable stop means may be provided to limit the degree of rotation to a value sufiicient to effect the desired electrical contact. Additionally, suitable keying means may be provided to avoid ambiguity in the insertion of the plug portions 45 and 46 in the proper channels 60 and 61.

From the foregoing description, it will be evident that the present invention has provided improved underwater connectors wherein all of the various advantages hereto fore set forth are fully realized.

What is claimed is:

1. A fluid proof electrical connector for underwater use comprising, in combination:

(a) a plug means carrying an externally exposed plug contact substantially flush with a surface portion of the plug means;

(b) a socket means having an internal wall portion carrying a socket contact substantially flush with a surface portion of the socket means; and,

(c) an insulating tumbler member in the form of a cylindrically shaped body in said socket means with a surface portion in full surface sliding engagement with said surface portion of the socket means, said tumbler having channel means defined by a cut out passage in spaced parallel relationship to the central axis of said cylindrically shaped body for receiving said plug means, said body being rotatable about its central axis from an initial position in which said socket contact is covered and insulated by said surface portion of said tumbler member to another position in which said plug contact is placed into electrical engagement with said socket Contact.

2. A connector according to claim 1, in which said plug contact is disposed in a laterally facing surface portion of said plug means, and in which said socket contact is disposed in an interior cylindrical side wall surface of said socket means, said cutout passage being in a pcripheral portion of said cylindrically shaped body.

3. A connector according to claim 1, in which said plug contact is disposed in a forwardly facing end surface portion of said plug means, and in which said socket contact is disposed in a rear fiat wall surface of said socket means laterally spaced from the center thereof said cutout passage extending from the front of said cylindrically shaped body to open out at the rear surface of said body.

4. A fluid proof electrical connector for underwater use comprising, in combination:

(a) a plug body having forwardly projecting smoothly surfaced plug means of electrically insulating plug material carrying at least one plug contact imbedded in said material and having an exposed plug contact surface substantially flush with an exterior surface portion of said plug material;

(b) a socket body having a hollow interior defined in part by a smoothly surfaced interior wall portion of electrically insulating socket material carrying at least one socket contact imbedded in said material and having an exposed socket contact surface substantially flush with an interior surface portion of said socket material; and

(c) a tumbler member of smoothly surfaced electrically insulating material received in said hollow interior of said socket such that peripheral surfaces of said member are in smoothly slidable engagement with said smoothly surfaced interior wall portion of said socket so that said member is guided for rotation within said interior about a central axis generally parallel to the direction of said forwardly projecting plug means from an initial position in which a smoothly surfaced portion of said tumbler covers and insulates said socket contact surface, said tumbler member including at least one channel means running parallel to and radially spaced from said central axis for receiving said plug means in a position in which said plug contact surface is engaged and covered by a smoothly surfaced interior wall portion of said socket spaced from said first mentioned smoothly surfaced interior wall portion of said socket, rotation of said plug means while in said channel rotating said tumbler member from its initial position to a position in which said plug contact surface engages said socket contact surface, the engaging surface of said interior wall of said socket wiping over said plug contact surface during rotation to remove any liquid or moisture therefrom prior to electrical engagement with said socket contact surface,

whereby said socket contact may continuously carry a given voltage without ever being exposed to water when connecting said plug contact to said socket contact.

5. A connector according to claim 4, including a water escape outlet extending from the interior rear portion of said socket behind said tumbler through said socket body to the exterior of said socket body, whereby water said interior and in said channel means is purged out through said outlet as said plug means is moved forwardly into said channel means of said tumbler member.

6. A connector according to claim 4, including interlocking means in said socket and plug bodies for securing said plug means in said socket after said plug means and tumbler member have been rotated relative to said socket body. v

7. A connector according to claim 4, in which said interior "wall portion of said socket body comprises a side wall of cylindrical shape, said socket contact surface being of concave cylindrical shape corresponding to said interior side wall and facing radially inwardly, said plug contact surface being of convex cylindrical shape and facing radially outwardly for complete engagement with said socket contact surface, peripheral surface portions of said tumbler member being dimensioned to slide smoothly on said cylindrical interior wall of said socket, to cover and insulate said socket contact surface when in said initial position.

8. A connector according to claim 4, in which said interior wall portion of said socket body comprises a rear end wall of fiat configuration, said socket contact surface being flush with said surface and radially and ciroumferentially spaced thereon to face forwardly, said plug contact surface being exposed on the front end of said plug means to face said rear wall of said interior, said tumbler member having a flat rear surface in flat surface engagement with said rear surface of said interior such that rotation of said tumbler member with said plug means received in said channel circumferentially positions said plug contact into engagement with said socket contact.

References Cited UNITED STATES PATENTS 1,901,040 3/1933 Peroni et al 200-5 1.09 2,741,749 4/1956 Smith 339-489 2,926,327 2/ 1960 Metelli 33941 3,291,926 12/1966 Nelson 200-51 MARVIN A. CHAMPION, Primary Examiner I. H. McGLYNN, Assistant Examiner US. Cl. X.R. 

